1. Field of the Invention
The present invention relates to a receiver circuit which receives serial data.
2. Description of the Related Art
In recent years, third generation cellular phone communication methods such as CDMA2000 (Code Division Multiple Access), W-CDMA (Wideband-CDMA), etc., have entered the mainstream. These communication methods provide communication at a remarkably high chip rate (or bit rate) as compared with second generation communication methods such as the GSM (Global System for Mobile communication) method, the PDC (Personal Digital Cellular) method, etc.
For example, the W-CDMA method, which is a third generation cellular phone communication method, requires transmission/reception of I/Q signals with a transmission data length of 10 bits and a reception data length of 8 bits between a digital baseband circuit (which will also be referred to simply as a “baseband circuit” hereafter) and an analog wireless communication unit (which will also be referred to as an “RFIC” hereafter) at a high speed of tens of MHz or more. With an arrangement in which parallel connection is provided between the baseband circuit and the RFIC, the baseband circuit and the RFIC must be connected to each other with several tens of signal lines. There is a large demand for small-sized cellular phone terminals. Accordingly, such an increase in the signal lines leads to a serious problem in cellular phone terminals.
In order to solve such a problem, as disclosed in Patent document 1, parallel/serial conversion is performed for 10-bit signals or 8-bit signals such that they are converted into high-frequency signals, thereby allowing the number of signal lines to be reduced.
[Patent Document 1]
PCT Japanese Translation Patent Publication No. 2004-519943
[Patent Document 2]
PCT Japanese Translation Patent Publication No. 2006-518130
However, the technique disclosed in Patent document 1 requires a synchronizing signal for identifying each bit stream, i.e., each word of data, which is used in a step of receiving serial data transmitted in a serial format. This requires additional signal lines. Such additional signal lines lead to an undesirable increase in the size of the set.